1. Field of the Invention
The present invention relates to a method of forming a fine pattern with a charged-beam technique such as a charged-beam delineation, and, more particularly, to a method of forming a pattern wherein the proximity effect is reduced.
2. Discussion of Background
Recently, very fine patterns of LSI devices have been required. Devices of a 0.5 .mu.m or even 0.25 .mu.m dimension will be developed in the near future. It is difficult for a conventional optical stepper to manufacture such microdevices. Consequently, demand has arisen for new and improved lithographic techniques. Among these, electron beam lithography is most promising.
However, electron beam lithography has a disadvantage in that a pattern of 1 .mu.m or less cannot be accurately formed due to scattering of the electron beam in a solid material, i.e., due to the promixity effect. For this reason, unceasing efforts have been made to prevent the proximity effect. For example, a multilayer resist technique, pattern size correction and beam dose correction (these corrections are performed by a main frame computer), high acceleration voltage application and the like have been proposed. However, none of these conventional techniques can satisfy the needs due to poor dimensional precision and a complicated process. It has been very difficult to date to decrease size errors to .+-.0.1 .mu.m for dimensional allowances (.+-.10%, i.e., 0.5 .mu.m.+-.0.05 .mu.m or 0.25 .mu.m.+-.0.025 .mu.m) in the patterns required for microdevices. Therefore, improved submicron electron beam lithography depends greatly on how pattern error, caused by the promixity effect, can be decreased.